The performance of Eq. (6) is also verified with the recent
experiment carried out by Shannag and Mourad [29]. They have
tested 150 mm diameter concrete cylinder confined with 2 and 4
layer mesh ferrocement jacket. The wire mesh was 12.6 mm
square opening and 0.94 mm diameter wire, having yield strength
of 385 MPa. The jacketing height was 280 mm. Table 8 shows the
experimental results of Shannag and Mourad and the predicted
results by using the current model [23]. The table clearly shows
excellent agreement between the test data of Shannag and Mourad
and predicted results using the current model [23]. The maximum
deviation is observed 7.4% for a specimen confined with 4 layer
mesh ferrocement jacket.
Although, the proposed model is based on maximum two layer
wire mesh, it can be applied for more than two layer wire mesh.
In the model, the equation for ‘‘confining pressure (fcf)’’ (Eq. (1)) is
developed based on the strain compatibility between the core concrete
and the external jacket; and the force equilibrium in any section
of confined concrete. Thus, the Eqs. (1) and (2) can be applied
for any number of mesh layer in the external ferrocement jacket.
Although, the value obtained for the confinement effectiveness
coefficient (K) is based on maximumtwo layer wire mesh, it can predict
the strength of concrete very closely that are confined by 4 layer
wire mesh. For a specimen confined with 4 layer mesh ferrocement
jacket, the maximum deviation between the predicted and the
experimental results is observed 7.4%; however, the minimum is
4.6% (Table 8). None of the previously proposed models can predict
the strength of confined concrete without a deviation from the
experimental results, and a 7% deviation is regarded as quite reasonable
[30]. Therefore, the equation can be applied for predicting the
strength of concrete confined by up to 4 layers of wire mesh.
5. Conclusion
In this study a total of 27 concrete cylinders with different size
were tested under monotonic compression. Based on the obtained
test results, the following conclusion can be drawn:
1. The external ferrocement jacket can enhance the load carrying
capacity, ductility and energy absorption capacity of concrete
specimens. This enhancement is more prominent in smaller
specimens.
2. The failure pattern and stress–strain behavior indicates that
single layer mesh ferrocement jacket cannot provide significant
external confinement. However, double layer mesh ferrocement
jacket can provide sufficient confinement to enhance the behavior
of confined concrete.
3. An analytical model is proposed to predict the strength of ferrocement
confined concrete. The predicted results agree very closely
with the test data available in the literature.